Field of the Invention
The present invention relates to an image processing apparatus which is particularly suitable to perform an image process using a reference frame, an image processing method which is performed by the image processing apparatus, a program which enables the image processing apparatus to perform the image processing method, and a storage medium which stores therein the program.
Description of the Related Art
Conventionally, as a general video process, an image process in which a plurality of frame images of different input times are used is performed. For example, in an IP (Interlace-Progressive) converting process, as in the method by Japanese Patent Application Laid-Open No. 2012-094960, a plurality of field images are read out of a memory, and used as reference images for constituting an image of an interpolation line. Moreover, in case of creating an interpolation image when converting a frame rate, as in the method by Japanese Patent Application Laid-Open No. 2004-297719, a process in which detection results of movement vectors of a plurality of frames before and after the interpolation image to be created are used is performed. In general, it is possible, by performing matching of corresponding points with reference to a larger number of frames and thus improving matching accuracy, to constitute a higher-accuracy interpolation image.
In general, if the number of frames to be referred is increased, many memory accesses are required, thereby increasing power consumption. In the video processing apparatus, if an image processing mode is set, then an image process is performed by referring to as many frames as the number according to the set modes. In a case where an image processing mode by which optimum image quality can be obtained is set, the frame images of which the number according to the set mode are read from the memory, and a suitable process is selected according to the feature of an area, and then the image process is actually performed. However, effectiveness of process effect is different according to the feature of an input image. More specifically, a significant difference may not occur in the processed results between a case where the process is performed by an image processing algorithm in which many frames are referred and a case where the process is performed by an image processing algorithm in which the frames of which the number is smaller than that in the former case are referred.
For example, in a frame rate converting process, if a still image is processed, it only has to repetitively output one frame without referring to a plurality of frames. Besides, if an interpolation image of the frame rate converting process is generated for a frame in which a light-dark difference is large within one frame, attention tends to be drawn to the light portion. Therefore, it is difficult to perceive deterioration of image quality in the dark portion even if the image process in which smaller number of frames are referred is performed. In other words, even in a case where the image process is performed by performing many memory accesses, the result obtained in this process may become the same degree as that in the case where the image process in which smaller number of frames are referred is performed. As a result, in this case, even when obtaining the image quality of the same degree, electric power is extra consumed to the extent that many accesses are performed.
The present invention has been completed in consideration of such problems as described above, and an object thereof is to enable a high-quality image process while reducing power consumption.